Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
  • B63B39/02—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses
  • B63B39/03—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by displacement of masses by transferring liquids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
  • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
  • B63B35/4413—Floating drilling platforms, e.g. carrying water-oil separating devices
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
  • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
  • B63B2035/4486—Floating storage vessels, other than vessels for hydrocarbon production and storage, e.g. for liquid cargo
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B39/00—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude
  • B63B39/06—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water
  • B63B2039/067—Equipment to decrease pitch, roll, or like unwanted vessel movements; Apparatus for indicating vessel attitude to decrease vessel movements by using foils acting on ambient water effecting motion dampening by means of fixed or movable resistance bodies, e.g. by bilge keels

Definitions

• This application relates to a vessel, preferably for petroleum activities, with carrying capacity generally comprised by one single hull, carrying a main deck and arranged for use in marine petroleum activity with treatment and storage of petroleum fluids both on the field and accosted under land.
• the application is on a large monohull vessel being applied for several different processes, e.g. a so-called "FPSO” ; a floating production, storage and off loading vessel, also performing processing of petroleum fluids, or a conversion plant especially for conversion of petroleum fluids to other, preferably fluid petroleum products, and not necessarily chemical processes but also physical processes, e.g. cooling to LNG.
• FPSO so-called
• the vessel is arranged for use both connected to the oil producing field via pipelines connected at a rotating turret in the vessel.
• the vessel also has a plane transom stern, thus it may lie with its stern to the quay.
• the vessel may be moved to other wells or along the quay where it may work with petroleum fluids delivered from gas storage tanks onshore.
• the vessel will be arranged with large storage tanks 11 for petroleum fluids in order to have a buffer capacity both if it in periods must receive more petroleum fluid than what can be processed, or if there are discontinuities in the reception petroleum fluid to be processed.
• the tanks 11 may be arranged with bulkheads and baffle plates and a design of the free surfaces in order to work out of phase with the vessel's rolling and pitching. Under stationary operation at sea, especially with a vessel performing continuous work in rough sea, the vessel will experience rolling, pitching and heave movements due to the waves.
• the rolling, pitching and heave movements will normally have each their dominating or natural frequency. Swell will also lead to slow rolling and heave even in calm sea.
• Periodic rotation movements as rolling and pitching are generally disadvantageous in that pressure, flow and forces in all processes on board vary due to the more or less periodic accelerations and rotations. It is also disadvantageous to the crew and their work operation that the vessel rolls and pitches. If these vessel movements are reduced in amplitude and frequency, the work on board may generally be done better and more efficiently. Further the wave movements from the vessel will propagate further to pipelines connecting the vessel with wells on the seabed, and to anchoring devices. It is desirable to reduce these vessel movements to a large extent.
• a vessel according to the present invention will thus have a longer proportion of operation time at harsh weather conditions.
• An additional moment of the invention is that by reduced roll- pitch and heave movements the load due to vertical acceleration and bending of risers, coiled tubing, and load on drilling fluid pumps, moorings and other equipment, is reduced to a lower level than by using vessels according to known art .
• Such problems with roll, pitch and heave moments and other wave movements may be counteracted by using the present invention comprising a vessel, preferably for petroleum processing and storage, which carrying capacity primarily is comprised by one single hull, with a main deck, and where the new and inventive trait is comprised by one, essentially horizontal dampening device reaching out on either side of the hull, under the water line, extending preferably along the entire length of the hull.
• a vessel according to the invention will for this purpose be very large and is arranged to carry a production plant and a processing or conversion plant for petroleum fluids, i.e. gasses and liquids. Several of these processes depend on stabile and relatively predictable pressure conditions.
• parts of the vessel's after end according to the invention will have an area of reduced heave, partly at the cost of a little increase of heave for the bow because the dampening device in the preferred embodiment of the vessel increases in width sternwards along the ship's side, and in addition cooperates with a second dampening device at the stern.
• the size of the vessel will do that the weakly increased heave motion of the vessel will not give a considerable disadvantage. Also there will not be performed any processing activity in the bow area because the vessel according to a preferred embodiment will have its crew section in the bow towards the weather due to small amounts of gas which can leak from such a large processing device.
• Another purpose with the vessel is that it shall be able to store petroleum fluids immediately after production from wells on the seabed and deliver and load petroleum fluids, either directly, or in processed form further to shuttle tankers which can tie up to transfer lines astern on this vessel.
• the width of the vessel's stern will then function as a breakwave where shuttle tankers may be situated completely or partly leeward of the vessel because the vessel in a preferred embodiment is designed to be turned with the bow towards the present weather, i.e. the combination of waves and wind.
• Fig. 1 describes schematically a horizontal plane view and section of the entire hull with a dampening devices according to the invention
• Figs. 2 and 2b describe schematically a vertical right-to- left section at A-A' , about astern of midship of the vessel
• Fig. 3 describes schematically a vertical athwartships section by B-B' a little afore of the transom stern.
• Fig. 4 displace a plane section of the main deck with the vessel situated with the stern alongside the quay.
• Fig. 5 shows a long section along the vessel and the front of the quay with the vessel lying ballasted down to a fundament on the seabed.
• Fig. 6 shows a sketch of a situation with a vessel according to the invention stationary in the open sea over a petroleum fluid producing well .
• Fig. 1 describes a schematic plane view and section of the vessel according to the invention with a waterline section of a hull 3 , and the plane view showing dampening devices 2 arranged below the waterline.
• the hull 3 has in a preferred embodiment even width, but may in alternative embodiments have other development of the width from the bow to the stern.
• the vessel has, afore of the midship, a rotating turret 14.
• the vessel's stern 32 is primarily plane and vertical, with a concave cavity 34 in the lower part of the transom stern 32 with the lower side of the cavity comprised by a dampening device 2 ' .
• the hull's cross section is extended by projections for extending generally in the entire height of the vessel from the bottom plate 40 and up to the main deck 1.
• the purpose with these projections 40 is to increase the vessel's directional stability so that it will direct itself towards the weather when it is moored at sea by means of mooring devices 400, via the rotating turret 14, e.g. when the vessel via and production risers 200 is situated connected to a well at the seabed with petroleum fluids .
• FIG. 3 show vertical cross sections of the vessel, with the wings or dampening devices 2 in the preferred embodiment arranged in level with the essentially plane bottom plate 40 of the vessel.
• the hull's 3 stern there is a concave cavity 34, with bottom of the cavity comprised by a second dampening device 2', which in a preferred embodiment generally is arranged in level with bottom plane 40 of the vessel. Due to that the dampening devices 2 and 2 ' are in level with and do not reach deeper than the vessel's bottom plane 40 the possibility exist to ballast the vessel and to set it down on a foundation along the quay.
• dampening devices 2 and 2' are preferably plate shaped and horizontal, they counteract both rolling, pitching and heave, contrary to if they should have been arranged vertically, a situation where they would not be able to counteract pitching and heave to a considerable degree.
• the vessel's hull 3 and dampening device 2 and 2' may be designed in steel, but it is in a preferred embodiment also possible to build considerable parts of the vessel in armed concrete.
• the vessel has a large width of the main deck 1.
• the main deck has an even width generally from bow area and the entire length back to the main deck's 1 end entirely at the stern of the vessel. This also reduce the risk that a wave coming in from the front and being higher than the freeboard to break in over the main deck 1 astern.
• the vessel's hull has a considerably narrower width of the hull 3 in the waterline than the main deck. This contributes to dampen the effect of vertical movements of the sea so that the vessel does not heave as much as it would have done with a larger area inside the waterline.
• Fig. 2 shows a schematic view and vertical cross section through the vessel, with the dampening devices 2 shown in section.
• One or more vertical openings 22 in the dampening device 2 are arranged for permitting a limited vertical flow-through of water and thereby give a dampening of the waves effect on the vessel, and at the same time to disperse the energy of the waves.
• the vessels rotation moment of inertia around the vessels main axis is increased due to two reasons : 1: A large mass is added represented by the dampening devices 2 situated thwartships of the vessels main axis and with a large separation from the main axis. 2 : A certain water mass is bound over each of the dampening devices 2, which are forced to partly follow the vessel's rotation movement when the dampening device 2 is on its way alternately at the starboard and the port side when the vessel rolls.
• a standing rim 24 on the dampening device 2 will contribute to reduce the overlying water masses (in relation to the dampening devices 22) possibility to flow sidewards, so that these water masses to a larger degree of forced with the rolling movement of the vessel.
• Additional dampening of the vessel's rolling may be achieved by arranging air filled tanks 26, shown in Fig. 2b, with opening only down toward the water, at either side of the vessel.
• the tanks 26 may have an alter wall 26'.
• Such stabilizing tanks 26 may be designed in under and in cooperation with the overhanging main deck 1 of the vessel out over the hull 3 outer side, and also to stiffen up the dampening devices 2 by means of vertical plates 26" standing between the hull 3 or main deck 1 and dampening devices 2.
• stabilizing tanks 26 outer wall 26' extend entirely or in partial connection with the standing rim 24.
• the vessel must be designed so large that the vessel's width is made preferably larger than the pronounced wave length which one wishes to avoid rolling with.
• Such a vessel with such a dampening device 2 will namely be forced to roll in phase with waves of a certain wavelength range in the order of the vessel's width.
• dampening devices 2 ' astern edge 21' towards the sea so that it extends like a generally convex ark 21' out from the vessel's stern 32, arranged for rejecting vessels which would come too close to the stern 32.
• dampening device 2 and 2' may consist of a frame with a lattice with several horizontally arranged lying plates with mutual separation or a grating of similar shape.
• the vessel is not designed to have its own propulsion engines but is designed to have propulsion by means of tender vessels . It will need tender vessels during transit.
• the vessel has power devices 8 for emergency propulsion and dynamic positioning.
• the hull 3 is hydrodynamically designed to be able to lay with the bow 33 towards the weather.
• Such power devices may be so-called "azimuth thrusters" with horizontal propeller axle arranged on a rotatable vertical stem comprising a vertical axle and gears, having the propeller power working freely rotatable through 360° all around the horizon.
• These power devices are in a preferred embodiment arranged astern at the starboard and port side of the hull 3 extending out through the bottom plane 40 under the projections 4.
• the projections 4 will give the vessel good directional stability with respect to the direction of the dominating weather, and reduce the need for machine power to lie in a good position towards the weather.
• Fig. 4 shows a schematic plane view of the vessel situated by the quay.
• the dampening device 2 has in a preferred embodiment several vertical openings 22 arranged to allow a limited vertical water through flow and thus imposes dampening of the waves' effect on the vessel. These openings are designed according to actual wave- and current conditions for ordinary operation.
• the dampening device 2 (2') with the openings 22 (22') will thus counteract and partially delay the flow-through of water and thus work as a fluid mechanical filter, especially on the vessel's sidewards rolling, and also vertical movement or heave, and also pitching.
• the effect of the filter is mathematically to reduce the high frequent amplitudes of the vessel's rolling and heave.
• the vessel shall comprise a transom stern 32 arranged to lie along a quay, shown in Fig. 5.
• Devices 340 are arranged for transport of materials in solid and fluid form, and energy, mainly between the vessel's stern and the onshore when the vessel is situated by the quay.
• the vessel may in this position under land receive gas from storage tanks or gas pipelines onshore, convert the gas to fluid petroleum products, e.g. diesel oil, which it exports onshore in to the quay afterwards.
• Fig. 5 shows further that the vessel may be arranged to lie on foundations at the seabed.
• An alternative solution is to moor the vessel in the ordinary way with bow moorings out into the sea and stern or quarter fast towards the quay.
• the vessel When the vessel is moored on the field, it may be moored by means of mooring devices 400, e.g. with anchor lines between the rotating turret 14 and suction anchors in the seabed, and such that the vessel receives petroleum fluids from wells on the seabed via risers 200. Together with the risers 200 there may also be arranged signal- and energy carriers for well control. Such a situation may be illustrated by Fig. 6, showing how the vessel may lie on the weather and convert gas which is being received through the pipelines 200. The gas is converted by means of a gas conversion plant 220 to other petroleum fluids.
• the bottom 40 of the vessel is in the invention not bound to be plane or horizontal and the dampening devices 2 are not either limited to lie level with the bottom or to have entirely plane shape or to lie entirely horizontal.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Civil Engineering (AREA)
• Architecture (AREA)
• Structural Engineering (AREA)
• Vibration Prevention Devices (AREA)
• Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
• Filtration Of Liquid (AREA)
• Specific Conveyance Elements (AREA)
• Float Valves (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=19901446

Family Applications (1)

Country Status (6)

Cited By (4)

Citations (3)

• 1997
  • 1997-12-12 NO NO975875A patent/NO310550B1/no unknown
• 1998
  • 1998-12-10 GB GB0014569A patent/GB2349372B/en not_active Expired - Fee Related
  • 1998-12-10 WO PCT/NO1998/000375 patent/WO1999030965A1/no active Application Filing
  • 1998-12-10 CA CA002314360A patent/CA2314360A1/en not_active Abandoned
  • 1998-12-10 AU AU15789/99A patent/AU1578999A/en not_active Abandoned
• 2000
  • 2000-05-26 DK DK200000840A patent/DK173813B1/da not_active IP Right Cessation

Patent Citations (3)

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